Maybe you can go home again, at least if it's summer and home is Southern Maryland. It's early June and Willem Roosenburg is heading out toward the river he grew up on. He's steering a small skiff along Washington Creek, a short, muddy-looking branch of the Patuxent River. The 49-year-old biologist is back from his teaching job at Ohio University and he's doing what he did first as a kid, then as a graduate student: He's looking for turtles.

It's the first day of his summer turtle-catching season, and under his wide-brimmed hat, Roosenburg sports a round face, a goatee, and the smile of a big kid let out of school. As he glides the skiff up to a fyke net, one of several he set out two days ago, he immediately starts an introductory lecture to a boatload of four assistants. Two of his assistants are undergrad students from the University of Maryland (where a diamondback terrapin named Testudo is the school mascot). They've heard the lecture before and begin hauling the net aboard.

His other assistants are hearing his talk for the first time. They're field biologists just arrived from faraway Myanmar, sent here for training by the Turtle Survival Alliance and the Wildlife Conservation Society, organizations alarmed by the possible extinction of the Burmese roofed turtle. This is the biologists' second day in Southern Maryland and their first experience with emptying fyke nets.

he fyke net, looking like a gigantic Slinky encased in fishnet, lies submerged in shallow water with several hoops breaking the surface like the humps of a small whale tethered to the shore. In the belly of this whale Roosenburg expects to find a number of northern diamondback terrapins (Malaclemys terrapin terrapin), a species that's been crawling around rivers like this for longer than humans have been walking on two legs. Turtles shared the earth with dinosaurs and somehow survived the mass extinction that wiped them out. Sometimes the race is to the slow.

"Let's show you how to get these turtles out of the net," Roosenburg tells his Myanmarese assistants, Khin Myo Myo and Kyaw Moe. As the net comes out of the water, several diamondbacks are clawing their way along the sides, their heads sticking through the net and swiveling on narrow necks like periscopes scanning for enemy ships. Most of them lose their grip and tumble backwards."You first go to the back of the net," Roosenburg says, "and you need two people." His helpers grab the back end and begin shaking out the net. A small pumpkinseed sunfish and several perch are soon flopping along the bottom of the boat. And crawling among them are seven terrapins.

Roosenburg picks up one of the larger terrapins, a female with a bright yellow underside and a distinctive diamond pattern on its shell, and holds it out. "Somebody want to hold her?" he asks. "She's a female. You can actually feel the eggs inside it, little hard round things that dimple." Myo Myo takes the turtle and hesitantly inserts her fingers under the shell. "I think she's probably 30 years old. And she's marked," Roosenberg says, pointing to notches along the rim of her shell. He put those notches there himself when he first caught this same turtle years ago, and those notches tagged her with a numerical I.D. that will stay with her the rest of her life. "This one's I.D. is 1R2R4R11R9L," he says, reading first the right side of her shell, then the left.

On this bright June morning, Roosenburg and his crew pick 24 terrapins out of five fyke nets along two muddy creeks, and 18 of them are clearly marked recaptures. The biologist gives more lectures on bagging terrapins and recording time and date and site of each capture. All field notes go into a yellow notebook.

Roosenburg is doing natural history, a traditional form of science that features time-consuming field work, close observation, and obsessive record keeping, all aimed at a fulsome description of organisms and their survival over time. Time in this case means 22 years. That's how long Roosenburg has been catching turtles in these creeks.

In his records are some worrisome signs. Roosenburg has not been catching as many turtles as he did just 10 years ago. Is Maryland's diamondback terrapin, like the Burmese roofed turtle, rapidly becoming an endangered species? Long-term records like his are rare because they're rarely funded. For his turtle work on the Patuxent, Roosenburg has been funded well for only seven of 22 summers. He and his wife have had to fund most of his research themselves.

Natural historians like Roosenburg may them-selves be an endangered species. Natural history may be dying out, much like some of the animals it once described in such loving detail. In recent decades major funding has been flowing into newer fields like cellular biology, molecular biology, systems ecology and mathematical ecology. Scientists in these fields are seen as rising stars working in cutting-edge research--a perception that's led to skimpy support for old-fashioned fields like natural history.

The results of these trends were spelled out in "The Impending Extinction of Natural History," a recent essay published in The Chronicle of Higher Education. "The natural historian has been pushed to the margins of academe," wrote co-authors David Wilcove, a conservation biologist, and Thomas Eisner, a pioneer in the field of chemical ecology. As universities fill up with specialists in the newer, hotter fields, those specialists are not likely to hire junior faculty in older fields like natural history. And that, the "deinstitutionalization of natural history," they write, "looms as one of the biggest scientific mistakes of our time."

The tendency today is to consider Natural History useful only if the animal being studied is seen as useful. In the Chesapeake Bay, the blue crab supports an important commercial harvest, and so does the rockfish, and once upon a time, so did the native oyster. All of these species have been and still are well studied. But what's the payoff, the thinking goes, from natural history work on a species like the diamondback terrapin? Such seems to be the naturalist's dilemma in the contemporary science climate: How do you run a long-term, largely unfunded study of a low-profit animal? And what good, after all, is your research?

Roosenburg is lecturing again, and this time everybody is listening. He and his assistants are crammed in a small field lab with five bags of turtles, getting ready for their first data-recording session of the season. Their makeshift lab is a small dark room in a red brick outbuilding that might have been a horse stable once upon a time.

The lab sits on a large farm estate several miles south of Benedict that holds a number of barns as well as two small cabins, where the student assistants bunk, and a creekside house along the west side of the Patuxuent, where Roosenburg and his family spend their summers. The whole setup comes with a low rent to Roosenburg and his crew, thanks to the good will of a longtime landowner who likes the idea of a local scientist doing long-range natural history on a native species. That's how Roosenburg runs his research on a low-profit species: He uses low-cost lab space and low-cost help, like undergrads.

His helpers are eager, but mostly untrained. Hence all the lectures. "You're looking at a turtle that is probably twice as old as you guys are," Roosenburg tells his assistants, holding up a large female he first caught in 1988. For this turtle and for every other one that comes out of his nets, he wants a dozen data points recorded, including time and place of capture, carapace (shell) length, width, height, mass, sex, and age. If it's a first-time turtle, he will give it an I.D., notching its shell with a drill and file. If it's a recapture, he wants the I.D. recorded along with any changes in size and condition. Everything goes into the computer, into the database.

As Roosenburg holds her, the turtle keeps twisting in his hands, oblivious to his lecture on field data, her claws paddling the air as she tries to crawl back to her home river. She's clearly a survivor, with the scars to show for it. "This is from spending a lot of time in pound nets," he says, pointing to scrape marks along her legs. Even that is considered data, and it goes into the computer too.One fact comes out of the computer immediately: This 40-something female has shown up in Roosenburg's nets 14 times in 20 years. Recapture rates like this are good news for the naturalist because every time this turtle reappears in his nets, she adds a new data point, making his demographic records even more robust. Other facts come out: This lady terra- pin seems to have lived her entire life within three miles of here. Four decades ago her mother dug a small hole, probably in sandy soil along a local creek, perhaps urinating to soften the ground. There she laid her eggs, most likely a baker's dozen.

Life in a turtle nest is either quiet or catastrophic--with catastrophes coming in the form of foxes or raccoons, both adept at sniffing out turtle urine and digging through the sand to feast on turtle eggs. This hefty female first came crawling out of her lucky nest as a tiny turtle, pea green and perfectly formed--and easy prey. She soon outgrew every male in the river, but did not reach sexual maturity until age eight or later. Thanks to her size she survived foxes and raccoons; thanks to luck, she survived watermen's nets and powerboats, two of the leading killers for large terrapins.

Every November or December, she hibernated, swimming to the bottom of a small, deep creek and digging herself into the mud for a long winter's sleep. Scientists call this brumation rather than hibernation, but by any term it's a neat trick for an air breather that normally likes to sun herself on rocks and tidal flats.

Once past puberty she began mating with males, and several times a year she dug her own nest and laid her own clutch of a dozen or more eggs. Each year, however, she found fewer nesting beaches as new homes replaced old farms and new owners put in more riprap and bulkheads and docks along their waterfronts. According to Roosenburg's numbers, perhaps only one in a hundred of her offspring is likely to survive.Pausing in his lecture, the naturalist looks the terrapin dead in the eye and smiles. It's not clear whether the biologist is catching the turtle or she's catching him. "Hey babe, how you doin'?" he asks, one survivor to another. "Welcome back."

Like the terrapin, Willem Roosenburg grew up on this river. His father, Bill Roosenburg, worked the Patuxent as a field researcher for the Chesapeake Biological Laboratory, and young Willem hung around with biologists and grad students, hitchhiked rides on the research boats, and learned to pull sampling nets. Like the sons of local watermen, he also learned to fish and boat and trotline for blue crabs. Rowing on the river one day, he spied small, dark bobbleheads popping up, then disappearing. Shipping his oars, he leaned over and suddenly saw turtles gliding under and around his boat, turtles by the dozens. He was floating through a herd of hundreds. An accidental vision that proved prophetic.After high school he left to become a biologist, starting his long, slow swim toward a PhD. When he started his dissertation at the University of Pennsylvania, he needed a field site for his research, and he thought again about the Patuxent. His father was there and was now struggling with health problems. And all those turtles were there.

During his first summer in the field, Roosenburg worked completely alone, setting out fyke nets, catching and marking terrapins, tracking down nest sites and checking the sex of little pea-green hatchlings as they came crawling out. His first focus was the odd connection between nest temperatures and the sex of hatchlings. When he came back for a second season, he was surprised by how many recaptures he was finding in his nets. That revelation opened the door to other research options, namely, demographic studies exploring how local ecology creates variations in life history traits. By the end of his third summer he was hooked. He realized he could do this the rest of his life.

After graduate school his life fell into a familiar rhythm. Fall, winter, and spring, he hibernated at Ohio University, digging out his own niche in an academic habitat. Every summer, he packed up his family for the annual migration back to his home river.

"To be quite frank with you, I love doing field work," Roosenburg admits. He's working his way through his sandwich at a picnic table next to his summer house. Lunchtime at his turtle camp is a do-it-yourself affair where he stocks the kitchen with bread and cold cuts and everyone makes his own. For the crew it's break time between finishing the lab work and hauling the turtles back out to the river, where they'll be released to go look for their own lunch.

Field work like this has its joys--and its sorrows. The joys can be heard in Roosenburg's lunchtime talk about tracking terrapins along the Patuxent. "I love being outside," he says. "That's the most important reason why I am a biologist." But there's a flip side: A working naturalist often comes face to face with the decline of the animals he's studying.

The best summers for Roosenburg --as a scientist and a Southern Marylander--were the seasons he spent working together with local watermen, catching fish in bank traps under his own commercial license and catching turtles for his research project. Bank traps are tall box-like cages used for catching gizzard shad, catfish, yellow perch and peeler crabs. When turtles also wander into these traps they usually survive. A proper trap stands tall enough that its top sticks up out of the water, letting air-breathing animals like turtles rise up, stick their heads above the water and breathe.

For Roosenburg, the bank traps were a bonanza. The income from his commercial catch bought fuel for the boat and paid room and board for his field assistants, and the incidental turtle catches added data to his growing demographic study of the species. On good days he was taking more than 100 turtles out of 35 bank traps. On his best day he hauled home 196 turtles, nearly all of them large females. Hard work every day, but for a Southern Maryland boy, it was the best of two worlds: He could be a waterman and a scientist.One of those worlds came to an end with the great bank trap conflict of St. Mary's County. As waterfront farms along the Patuxent gave way to new homes during the 1990s, many of the arrivistes from the cities and suburbs began complaining. Bank traps with their stakes and nets were spoiling the view from the lawn, and some watermen refused to move their traps, citing fishing rights that dated back hundreds of years. The result was an angry dispute between watermen and landowners--the kind of culture clash, full of ironies, that has become familiar in the Tidewater regions of Maryland.

Caught in the cultural crossfire were the scientist and the terrapin. As the battle heated up, moving from local disputes toward legislative action, Roosenburg lobbied to keep the bank trap tradition alive, partly out of friendship with watermen, partly out of self-interest in his large turtle hauls, partly out of fear for what could follow--and did. As soon as the 2001 legislature banned bank traps in St. Mary's County, watermen turned to fyke nets, and Roosenburg's worst fears came true. Fyke nets can be death traps for turtles: they don't stick up above the water like bank traps, not unless a float is inserted to create space for air breathers. While Roosenburg kept floats in his fyke nets, many watermen did not. Soon, turtles were drowning in large numbers.

Soon, too, Roosenburg lost his long-standing friendships with local watermen. When officials from the Department of Natural Resources (DNR) later closed down commercial fyke netters for illegally keeping blue crabs, the penalty enraged some local watermen and left the terrapin biologist as the only legal fyke netter. Watermen immediately blamed Roosenburg, sometimes confronting him on his collecting trips. "They swear that I was the one that turned them in," he says. "You mention my name to those guys, and they'll call me the biggest a**hole in Southern Maryland."

Maybe you can go home again, but you can't step twice in the same river. By the summer of 2001, bank traps were gone, watermen were angry, nest sites were disappearing, an oil spill was killing hundreds of turtles, and his father was dying. "That all happened in one bang," he says. "Those were the dark days of my life."

Roosenburg quietly applied himself to the task of saving the estuary's oldest inhabitant, using his years of accumulated data to push for a variety of changes, including limiting lethal bycatches of terrapins by recreational crabbers and banning commercial harvesting of terrapins for the exploding China market. He documented how turtles had probably been drowning for decades in all those crab pots hanging off community and private docks. Not many people notice, says Roosenburg, because these accidental kills wiped out turtle populations years ago in many rivers.

One of his key findings helped Maryland terrapins survive a new threat that began not in the Chesapeake, but in China. In the 1990s, China began importing increasing numbers of turtles for consumers who thought turtle meat could fight cancer, enhance virility and extend longevity. The China trade began decimating turtle populations in Myanmar, Vietnam, Borneo, Java and Sumatra. Conservationists called it the "Asian turtle crisis," and began warning that an American turtle crisis could be next. In Maryland, local groups began lobbying the legislature to close down the commercial fishery for diamondback terrapins. Harvest records were incomplete but showed an industry that was small--but ready to go through the roof, given the Chinese demand. For 2002, DNR estimated a harvest of only 151 terrapins. Four years later, however, the harvest total jumped to 11,010 terrapins--by only 14 licensed watermen. If the boom in the China trade were to draw hundreds more into havesting terrapin, it would set off a turtle fishing boom that could prove disastrous.The new lobbying campaign lasted several years, with Roosenburg playing an advisory role as a low-key but persistent member of the Chesapeake Terrapin Alliance. "He was quietly advising us that this was not a species that needs a fishery in the face of a declining spawning habitat," says Harley Speir, a fishery manager for DNR. In 2006, the campaign won a partial ban based on turtle size--but the harvest actually increased. The next legislature enacted a complete ban on the commercial harvest of the diamondback terrapin, and in March 2007 Governor Martin O'Malley quickly signed it into law.

Some of the clinching evidence had come from Roosenburg's work. Called to testify before legislators, the biologist spelled out a take-home message from the only long-term study of terrapins in the Bay: In the last 10 years, terrapin populations had already declined 75 percent in his home river, said Roosenburg, with hardly any commercial harvest in the region. A boom in the harvest could quickly drive the species down for decades. Local research carries weight because it is local, suggests Speir. "It was significant," he says of Roosenburg's research. "It was the only real data we had for this area."

Next to a canal-like creek on the east side of Poplar Island, Roosenburg kneels down and pulls three little green hatchlings out of a bag. He sets them gently on a small, stony beach bordered by thick, high-standing marsh grasses. The hatchlings stand motionless for a good 30 seconds, then one clambers over a stone, slips into the water and begins waving its legs like it wants to swim. The other two look around, then clump off toward the marsh grass.

The biologist snatches them up and plunks them back at water's edge where they glance around again, then finally take the first plunge. "Okay guys, have fun," says Roosenburg. "See you in a few years."

It's his last field day for the summer, and he's spending it on Poplar Island, the site of his second field research study. Since 1998, the U.S. Army Corps of Engineers has been diking and filling around this eroded island to construct a large holding site for dredge material that is dug out of the shipping channels of the Chesapeake Bay every year. One key question for the Corps: Can this new/old island also become a habitat for birds and, perhaps, for terrapins? That's why Roosenburg is here.

To keep track of terrapin births on the site, the biologist has two assistants work the island every day. Ryan Trimbath and Tony Frisbee, both blond and slightly sunburned, patrol the island's new wetlands, looking for nests, capturing and tagging and releasing hatchlings. Everything--the number and location of nests and hatchlings--goes into notebooks and then into the computer.

Answers are already coming out of the database they've built, answers that bode well for Roosenburg's hopes for a terrapin restoration. Back in the Patuxent, about one hatchling out of a hundred survives, but here on Poplar, more than 70 out of a hundred survive. Poplar has no commercial harvesting, no foxes and raccoons, no riprap or bulkheads blocking off the beach--and, just as important, no crab pots or fyke nets to drown in. The only predators so far seem to be birds. If the 70 percent survival rate keeps up, the Corps could rename the place Turtle Island.

What does Poplar Island mean for the mainland? After his dark years on the Patuxent, the Poplar Island experience has been hope-inducing for Roosenburg. The experience here stands as a rough "proof of concept" for some key steps that could be tried elsewhere. The ban on commercial harvesting is now in place, says Roosenburg, but more is needed.

Watermen should check their traps and nets regularly (as many already do), recreational crabbers should fit their pots with bycatch reduction devices (as they are now legally required to do), and landowners should begin replacing riprap and bulkheads with "living shorelines" that are graded and vegetated (as some are doing already).

With those threats taken out of the equation, terrapins might quickly come back to the mainland rivers, where they were always part of the life and spirit and sense of place in tidewater Chesapeake, a part of a world where a boy in a boat could look down and see hundreds of terrapins passing by.

Reaching into a long tan bag, Roosenburg grabs another handful of little hatchlings and holds them up for picture-taking. This morning's launch is being staged for two writers, two photographers, and a videographer. The new harvest ban seems to have stimulated more press interest, both in the diamondback terrapin and in the biologist who has built a career trying to save them.

Roosenburg has only 15 hatchlings to release this morning, but the ritual goes slowly, with frequent retakes and multiple camera angles. Each baby terrapin gets a well photographed bon voyage. "When we have 150 of these to release," the biologist chuckles, "there's a lot less ceremony."

Finally he pulls the last terrapin from the bag, the last release for Roosenburg's summer before he migrates back to academe. Atop a small gray stone, the lone diamondback stands its ground, tiny and charismatic and eerily confident, the newest apparition of the oldest animal life in the estuary.

Michael W. Fincham is a writer and documentary producer with the Maryland Sea Grant College. This article was adapted with permission from his article in the December 2008 issue of Chesapeake Quarterly.